The primary objectives of this Phase 3, randomized, double-blinded, placebo-controlled trial are (1) to demonstrate the efficacy of GV150526, a glycine antagonist and cerebral neuroprotectant, by showing improvement in functional outcome (independence) at 3 months in patients with acute ischemic stroke presenting within 6 hours of symptom onset; and (2) to demonstrate safety of GV150526 in acute stroke.